warning ADT

Error Code Alarm

An intrusion has been detected and the system is armed.

? What Causes This

Detected intrusion via sensors.

How to Fix It

Identify and secure the breached zone, then disarm/rearm as necessary.

Source: page 19 of the official manual

From the manual

Manual page 19 — ADT error Alarm

This error code appears in:

ADT Safewatch Pro 3000